Series or parallel ?

08-30-2017, 03:53 AM

I have an inverter which has minimum requirement of 120 volts DC to work - i have 8 panels ready to install . Any expert would let me know which option i should select to instal - number 1 option is 4 in series X 2 arrays

or

option 2 = 8 in series

Both option will work for sure , my location has some partial shading issue too . So please let me know which one i should go for ? and what measures i should take to prevent any damage to solar panel / cells When partial shade will come on one array ?

I have an inverter which has minimum requirement of 120 volts DC to work - i have 8 panels ready to install . Any expert would let me know which option i should select to instal - number 1 option is 4 in series X 2 arrays

or

option 2 = 8 in series

Both option will work for sure , my location has some partial shading issue too . So please let me know which one i should go for ? and what measures i should take to prevent any damage to solar panel / cells When partial shade will come on one array ?

Thanks

Nadeem Ahmed

You have not told us what your panel voltages are, nor have you told us the maximum voltage for the inverter input.
If, for example, your panel Voc is 32V and you have cold winters the winter morning Voc might be as high as 40V. Times 8 panels gives you 320V. Can the inverter take that high a voltage without damage?

If so, then the single string of 8 would give you the lowest current and therefore allow the smallest DC wires.
Partial shading of a single string can force the bypass diodes of one or more panels to conduct, dropping the string voltage by up to the full Vmp of the shaded panel. But the rest of the panels will deliver full power.
If you use two strings of 4 panels each, one shaded panel could drop the working voltage of its string enough that when used in parallel with an unshaded string it will not contribute any power at all to the inverter.
If your inverter has two MPPT inputs, then two strings of 4 might be more practical. But at the same time, one shaded panel could drop that string's effective voltage below 120V.

Give us more details on your system and we can give more specific advice.

Comment

Both option will work for sure , my location has some partial shading issue too . So please let me know which one i should go for ? and what measures i should take to prevent any damage to solar panel / cells When partial shade will come on one array ?

Partial shade will not damage any solar panel. It will reduce the power available from that string. Optimizers (like the Tigo line) can help there, as can going to a microinverter system or a SolarEdge inverter (also requires optimizers.)